Fuse plug



Aug. 28, 1945, a HOLMES I 2,383,484

' FUSE PLUG Filed Nov. so, 194::

George EJIaLmes ATTORNEYS Patented Aug. 28, 1945 UNITED sTATas PATENT; :orrica Y FUSE am George HolmeaDearliormMich'. n Application November 30, 1943, Serial No. 512,372

7 v2 Claimsn (Gram 255,

The invention relatesto an electrical fuse unit,

and more especially to a multiple replaceable fuse unit involving refinements overthe 'subjecte matter of Letters Patent'No. 2,102,206, issued on or about Decemberfl i, 193'7. 'Ihe primary object of the presentinvention is the' provisionof' a fuse uni-t ofthis character, wherein a carrier for a plurality of fuse elementsis adjustably supported in a plug receptacle, so that a ratchet acting contact is engageable with any one of the plurality of fuse elements other than the spent one, forthe renewal thereof, to bring the substituted fuse element into service and into electrical contact with the contact members in said receptacle.

Another object of the invention is' the provi-.

sion of a fuse of this character, wherein the same in its entirety constitutes refinements over the subject-matter of Letters Patent Nd. 2,102,206, issued on or about December 14, 1937.

A further object of the invention is the provision of a fuse unit of this character, wherein the fuse carrier is rotatably fitted within the receptacle therefor, and is constructed to carry a plurality of renewable fuse elements which may besuccessively brought into service for the continued use of the fuse unit, and these elements are replaceable when spent, the unit being unique and novel in its structural make-up.

A still further object of the invention isv the provision of a fuse unit ofthis character, which is extremely simple in construction, thoroughly reliable and efficient in operation, strong, durable, readily and easily adjusted, conveniently assembled, and inexpensive to manufacture.

With these and other objects in view the invention consists in the features of construction,

combination and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawing, which shows the pre-. ferred embodiment of the invention, and pointed out in the claims hereunto appended. A

In the accompanying drawing:

Figure 1 is a vertical sectional view of the fuse i Figure 5 is a side view ofan insulating ring or collar of the unit. I v Figure 6 isa top plan view thereof. I

Figure '7- isa further transverse sectional" view through the unit.

Similar reference characters indicate corresponding parts throughout'the several views in the drawing. a

Referring to the drawing in detail A designates generally the electrical fuse unit in its entirety constructed in accordance with the invention as hereinafter set forth.

The unit A comprises a receptacle I0, preferably made from glass or other transparent material, provided with a central circular socket II, which opens through one end of the said receptacle, while the other end of the said socket is closed by a head portion I2 of the receptacle. A threaded metal shell I3 encircles the open end of the receptacle I0, exteriorly of the latter, and is threaded thereon in the conventional manner.

Adapted to be removably fitted in the receptacle I0 to have encasement by the latter is a fuse carrier I4 formed with a truncated conical central core I5 which is designed to be confined within the socket II, and this core is integral with a circular closure cap I6, the carrier I4 being entirely formed from glass or other transparent material. The core I5. longitudinally thereof is provided with spaced radial ribs I1, effecting therebetween channels or grooves I8, these being formed with sloping bottoms I9, while the ribs are straight throughout.

Disposed within the channels or grooves are strip-like fuse elements 20, each having a fusing portion or area 2I, and these elements extend from a crowning web 22 for the core I5. The web 22 is held fast to'the core I5 by a contact post 23 fitting the longitudinal central axis of the carrier I4, and terminally protrudes at 24 through a knob-like lug 25 on the outer side of the cap I6 for electric contact purposes when the unit A is screwed into an electric distributing socket member.

Concentrically arranged on the carrier I4 next to the cap I6 thereof is a split insulating retainer ring 26, which when in place is overhung by the shell I3 for confinement thereby when the carrier I4 is inserted in the socket II in the receptacle I0, so that a metal contact spring 21 will be held engaged with one of the fuse elements 20 and the shell I3, respectively. This spring 21 will have ratchet action on the ribs I1 when the carrier is turned or rotated in the receptacle, to

bring such spring into contact with another element 20, should the previous element having contact with such spring have become spent or fused.

The shell I3 in this manner is the other contact of the fuse unit A. The receptacle It at the wall of the socket H is flat faced at 28 next to the closed end of the socket so as to frictionally hold the carrier l4 against rotation within the receptacle l0 when such carrier is fully inserted in the latter, it being necessary to partially extract the carrier from the receptacle should it be desired to turn or rotate the said carrier for a changing of a fuse element.

In the operation of the invention the fuse unit A, assembled as shown in Figure 1 of the drawing, is threadedly inserted in a fuse box or sodltt member in a well known manner, and completes an electrical circuit thereby until an overload occurs suificiently to blow the fuse. When this happens the unit is removed from the honor member and adjustment is made to the unit for setting-up a new fuse element therein to enable the unit to be fin'ther used.

When all of the fuse elements 20 have been spent then a new carrier is inserted in the receptacle with its fuse element set-up.

What is claimed is:

1. A fuse unit of the kind described, comprising a receptacle having a cylindrical socket of uniform diameter therein opening through one end only of the receptacle, a fuse carrier formed with a tapered core inserted within socket of the receptacle and spaced ribs extending outwardly of the core and having outer edges paralleling the inner wall of the socket, fuse elements arranged concentrically of the core, in spaced relation to each other, an electric contact centrally of the carrier and common to the fuse elements, a, threaded shell-like contact exteriorly engaged on the receptacle next to the open end of the socket, springy ratchet acting contact means selectively engaging the fuse elements and the shell-like contact, respectively, a retaining means fitting the core of the carrier for holding the contact means in working position with respect to the elements and shell-like contact, and a flattened portion interiorly of the socket for engaging faces of the ribs for holding the carrier against rotation in the receptacle when the said carrier is fully inserted in the latter.

2. The invention as defined in claim 1 wherein said ribs have their side faces flared outwardly and their and faces converging outwardly toward an outer edge portion adiacent the inner wall of the socket, and wherein the flattener portion engages an end face of two adiaoent ribs for holding the carrier against rotation when fully inserted in the socket.

GEORGE E- HOLMES. 

